1. Field of the Invention
This invention is directed to the alkylation or transalkylation of aromatic hydrocarbons including aromatic hydrocarbons containing a non-polar substituent, e.g. benzene or toluene, with an alkylating or transalkylating agent, e.g. an olefin or a polyalkylaromatic hydrocarbon, wherein the alkylation or transalkylation is performed in the presence of a catalyst composition comprising a zeolite selected from the group consisting of ZSM-35, ZSM-38 and a combination thereof, said zeolite being characterized by long catalyst life, being capable of affording high selectivity to desired products, e.g. alkylaromatics, and being easily and effectively regenerated, when necessary, without substantial loss in activity.
2. Description of the Prior Art
Alkylation of aromatic hydrocarbon compounds employing certain crystalline aluminosilicate zeolite catalysts is known in the art. For instance, U.S. Pat. No. 3,251,897 describes liquid phase alkylation in the presence of crystalline aluminosilicates such as faujasite, heulandite, clinoptilolite, mordenite, dachiardite, zeolite X and zeolite Y. The temperature of such alkylation procedure does not exceed 600.degree. F. for use of any of the aluminosilicates as catalyst.
Also, U.S. Pat. No. 2,904,607 shows alkylation of hydrocarbon compounds in the presence of certain crystalline aluminosilicate zeolites. The zeolites described for use in this patent are crystalline metallic aluminosilicates, such as, for example, magnesium aluminosilate. U.S. Pat. No. 3,562,345 shows transalkylation of toluene over a zeolite catalyst typified by mordenite, e.g. Zeolon (see comparative examples hereinafter presented). U.S. Pat. No. 3,668,264 shows alkylation of aromatic hydrocarbons over several synthetic and naturally occurring zeolites, not including synthetic zeolite ZSM-35 and ZSM-38. One naturally occurring zeolite mentioned as suitable in the latter patent is ferrierite (see comparative examples hereinafter presented).
U.S. Pat. Nos. 3,631,120 and 3,641,177 describe a liquid phase process for alkylation of aromatic hydrocarbons with olefins in the presence of certain zeolites. U.S. Pat. No. 3,631,120 discloses use of an ammonium exchanged, calcined zeolite having a silica to alumina mole ratio of between 4.0 and 4.9. U.S. Pat. No. 3,641,177 discloses use of a zeolite catalyst activated in a particular manner.
Unfortunately, while many of the crystalline aluminosilicate catalysts proposed for such alkylation methods provide satisfactory initial yields of desired products, for the most part, their catalytic aging properties are not sufficiently good enough to warrant commercial application. Hence, it is of advantage to provide a satisfactory process for alkylating or transalkylating aromatic hydrocarbons, depending upon whether an alkylating or transalkylating agent is employed, using a crystalline aluminosilicate zeolite catalyst which has improved aging properties, i.e. maintains alkylation or transalkylation in high yield over a long, commercially attractive period of time, heretofore lacking in the art.